Alloy. A mixture of two or more metals combined to achieve properties, such as a lower melting point or greater strength, that the individual metals do not possess.

Butt Joint. A solder joint where the end of the lead sits on the solder pad.

Body. The insulating part of an interconnect.

Capillary Action. The effect of surface tension that draws a liquid into a small opening.

Contact. The conducting part of an interconnect at the interface between the connector and the lead on the device being connected.

Convection. The transfer of heat by movement of hot air. Often used in conjunction with infrared radiation to reduce the effect of IR shadowing.

Coplanarity. The distance between the lowest and highest lead when the connector is laying in its seating plane.

Dewetting. A situation where a lead or pad was at one point in the soldering process wetted by the solder, but due to extended time or temperature, the presence of intermetallics, volatiles or other causes, has become withdrawn from the wetted surface.

DIP Socket. A connector for a Dual In-Line Package, or one that has its leads in two parallel rows.

Electroplating. A method of electrically depositing metals of very precise compositions and thicknesses onto a base metal.

Eutectic Solder. The most common solder alloy because of its low melting point (183°C), composed of 63% Tin and 37% Lead.

Fillet. A smooth, concave junction where two surfaces meet. The quality of a solder fillet determines the strength of the joint.

Fluorocarbon. The liquid vaporized in Vapor Phase reflow soldering.

Footprint. The pattern on the printed circuit board to which the leads on a surface mount component are mated. Also called a land or a pad.

Gull Wing. A surface mount lead configuration where the leads are normally bent out and are parallel to the bottom of the interconnect and to the board.

Heat Treating. A process that uses precise heating and cooling of metals after stamping and forming in order to optimize internal stresses and spring properties.

IR Shadowing. When connector bodies or other components prevent the infrared energy from directly striking some solder joints, causing non-uniform heating.

IR Reflow. A soldering process that uses infrared (IR) light with a wavelength between visible light and microwave radiation as its energy source.

Intermetallic. Chemical compounds formed between the metals present in the solder, base metal and protective platings. Intermetallic formation is necessary for good solder joints, but excessive intermetallics can cause brittleness.

J-Lead. A surface mount lead configuration where leads are bent into curves. Infrequently used on interconnects.

Land. The metal portion of a printed circuit board where the leads on a surface mount component are mated. Also called a footprint or a pad.

Leaching. The movement of metal atoms from the lead base metal into liquid solder. This is prevented by nickel plating. May also refer to alloying of a gold protective plating into the solder.

Pad. The metal portion of a printed circuit board where the leads on a surface mount component are mated. Also called a footprint or a land.

Pitch. The centerline spacing of the leads on an interconnect.

PLCC Connector. A connector that mates with a Plastic Leaded Chip Carrier.

Printed Circuit Board. An epoxy glass and metal composite on which circuits are etched and to which active, passive and hardware components are attached. Also called a PCB or PC Board.

Plated Through-Hole. A hole through a Printed Circuit Board that has been electropated and into which a lead is placed and soldered for electrical and mechanical connection.

Reflow Soldering. The process of screen printing solder paste and then heating it to cause it to melt, or Òreflow,Ó to wet the leads and pads around it.

Self Alignment. The tendency of leads to center themselves on solder pads due to the surface tension of the liquid solder.

Surface Mount Device (SMD). An active or passive device designed to be soldered to the surface of the printed circuit board.

Surface Mount Technology (SMT). The process of assembling printed circuit boards with components soldered to the surface rather than to plated through-holes.

Solder Paste. A mixture of solder powder, flux, solvents and binder that is screen printed onto the printed circuit board and then reflowed to form the solder joints.

Vapor Phase Soldering. A soldering process that uses the latent heat of vaporization of a liquid as its energy source.

Wave Soldering. The most widely used mass soldering process, primarily for through-hole boards, where the board is passed over a wave of solder which laps against the bottom of the board to wet the metal surfaces to be joined.

Wetting. The ability of liquid solder to attach itself to the surfaces being joined through the formation of intermetallic bonds.